package ca.tatham.triplipse.wizards;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.lang.reflect.InvocationTargetException;
import java.net.URL;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.operation.IRunnableWithProgress;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.wizard.Wizard;
import org.eclipse.ui.INewWizard;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchWizard;
import org.eclipse.ui.PartInitException;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.ide.IDE;
import org.osgi.framework.Bundle;

import ca.tatham.triplipse.Activator;

public abstract class NewRdfWizard extends Wizard implements INewWizard {

	private NewRdfWizardPage m_page;
	private ISelection m_selection;

	public NewRdfWizard() {
		super();
		setNeedsProgressMonitor(true);
	}

	protected abstract String getSampleRdfFile();

	protected abstract String getFileExtension();
	
	protected NewRdfWizardPage createPage(ISelection selection) {
		return new NewRdfWizardPage(selection, getFileExtension());
	}

	public void addPages() {
		m_page = createPage(m_selection);
		addPage(m_page);
	}

	/**
	 * This method is called when 'Finish' button is pressed in the wizard. We
	 * will create an operation and run it using wizard as execution context.
	 */
	public boolean performFinish() {
		final String containerName = m_page.getContainerName();
		final String fileName = m_page.getFileName();
		IRunnableWithProgress op = new IRunnableWithProgress() {
			public void run(IProgressMonitor monitor)
					throws InvocationTargetException {
				try {
					doFinish(containerName, fileName, monitor);
				} catch (CoreException e) {
					throw new InvocationTargetException(e);
				} finally {
					monitor.done();
				}
			}
		};
		try {
			getContainer().run(true, false, op);
		} catch (InterruptedException e) {
			return false;
		} catch (InvocationTargetException e) {
			Throwable realException = e.getTargetException();
			MessageDialog.openError(getShell(), "Error", realException
					.getMessage());
			return false;
		}
		return true;
	}

	/**
	 * The worker method. It will find the container, create the file if missing
	 * or just replace its contents, and open the editor on the newly created
	 * file.
	 */
	void doFinish(String containerName, String fileName,
			IProgressMonitor monitor) throws CoreException {
		// create a sample file
		monitor.beginTask("Creating " + fileName, 2);
		IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
		IResource resource = root.findMember(new Path(containerName));
		if (!resource.exists() || !(resource instanceof IContainer)) {
			throwCoreException("Container \"" + containerName
					+ "\" does not exist.");
		}
		IContainer container = (IContainer) resource;
		final IFile file = container.getFile(new Path(fileName));
		try {
			InputStream stream = openContentStream();
			if (file.exists()) {
				file.setContents(stream, true, true, monitor);
			} else {
				file.create(stream, true, monitor);
			}
			stream.close();
		} catch (IOException e) {
			// do nothing
		}
		monitor.worked(1);
		monitor.setTaskName("Opening RDF file " + fileName + "for editing...");
		getShell().getDisplay().asyncExec(new Runnable() {
			public void run() {
				IWorkbenchPage page = PlatformUI.getWorkbench()
						.getActiveWorkbenchWindow().getActivePage();
				try {
					IDE.openEditor(page, file, true);
				} catch (PartInitException e) {
					// do nothing
				}
			}
		});
		monitor.worked(1);
	}

	/**
	 * We will initialize file contents with a sample text.
	 */

	private InputStream openContentStream() {
		String content = getDefaultContent();
		return new ByteArrayInputStream(content.getBytes());
	}

	public String getDefaultContent() {
		return getContent(getSampleRdfFile());
	}

	public static String getContent(String file) {
		Bundle bundle = Activator.getDefault().getBundle();
		URL resource = bundle.getEntry(file);
		if (resource != null) {
			try {
				InputStream stream = resource.openStream();
				Reader reader = new InputStreamReader(stream);
				char[] buffer = new char[stream.available()];
				reader.read(buffer);
				return new String(buffer);
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

		return "";
	}

	private void throwCoreException(String message) throws CoreException {
		IStatus status = new Status(IStatus.ERROR, "ca.tatham.triplipse",
				IStatus.OK, message, null);
		throw new CoreException(status);
	}

	/**
	 * We will accept the selection in the workbench to see if we can initialize
	 * from it.
	 * 
	 * @see IWorkbenchWizard#init(IWorkbench, IStructuredSelection)
	 */
	public void init(@SuppressWarnings("unused")
	IWorkbench workbench, IStructuredSelection selection) {
		this.m_selection = selection;
	}
}